1. Technical Field
This application relates to the field of physical access control, and more particularly to the field of access control using processor actuated locks and related data.
2. Description of Related Art
Ensuring that only authorized individuals can access protected areas and devices may be important in many instances, such as in the case of access to an airport, military installation, office building, etc. Traditional doors and walls may be used for protection of sensitive areas, but doors with traditional locks and keys may be cumbersome to manage in a setting with many users. For instance, once an employee is fired, it may be difficult to retrieve the physical keys the former employee was issued while employed. Moreover, there may be a danger that copies of such keys were made and never surrendered.
Smart doors provide access control. In some instances, a smart door may be equipped with a keypad through which a user enters his/her PIN or password. The keypad may have an attached memory and/or elementary processor in which a list of valid PINS/passwords may be stored. Thus, a door may check whether the currently entered PIN belongs to the currently valid list. If so, the door may open. Otherwise, the door may remain locked. Of course, rather than (solely) relying on traditional keys or simple keypads, a more modern smart door may work with cards (such as smart cards and magnetic-strip cards) or contactless devices (e.g., PDA's, mobile phones, etc.). Such cards or devices may be used in addition to or instead of traditional keys or electronic keypads. Such magnetic-strip cards, smart cards or contactless devices, designed to be carried by users, may have the capability of storing information that is transmitted to the doors. More advanced cards may also have the ability of computing and communicating. Corresponding devices on the doors may be able to read information from the cards, and perhaps engage in interactive protocols with the cards, communicate with computers, etc.
An aspect of a door is its connectivity level. A fully connected door is one that is at all times connected with some database (or other computer system). For instance, the database may contain information about the currently valid cards, users, PINs, etc. In some instances, to prevent an enemy from altering the information flowing to the door, such connection is secured (e.g., by running the wire from the door to the database within a steel pipe). On the other hand, a totally disconnected door does not communicate outside of its immediate vicinity. In between these two extremes, there may be doors that have intermittent connectivity (e.g., a wirelessly connected door that can communicate with the outside only when within range of a ground station, such as the door of an airplane or a truck).
Traditional access control mechanisms suffer from many drawbacks. Fully connected doors may be very expensive. The cost of running a secure pipe to a distant smart door may vastly exceed the cost of the smart door itself. Protecting a wire cryptographically, while possibly cheaper, still has its own costs (e.g., those of protecting and managing cryptographic keys). Moreover, cryptography without steel pipes and security guards cannot prevent a wire from being cut, in which case the no-longer-connected door may be forced to choose between two extreme alternatives: namely, remaining always closed or always open, neither of which may be desirable. In any case, fully connecting a door is often not a viable option. (For instance, the door of a cargo container below sea level in the middle of the Atlantic Ocean is for all practical purposes totally disconnected.)
Disconnected smart doors may be cheaper than connected doors. However, traditional approaches to smart doors have their own problem. Consider, for instance, a disconnected smart door capable of recognizing a PIN. A terminated employee may no longer be authorized to go through that door; yet, if he still remembers his own PIN, he may have no trouble opening such an elementary smart door. Therefore, it would be necessary to “deprogram” the PINs of terminated employees, which is difficult for disconnected doors. Indeed, such a procedure may be very cumbersome and costly: an airport facility may have hundreds of doors, and dispatching a special team of workers to go out and deprogram all of such doors whenever an employee leaves or is terminated may be too impractical.
Accordingly, it is desirable to provide a level of security associated with fully connected doors without incurring the additional costs and other drawbacks thereof.